- Your Indian mobile number is not just a phone number. It is the second factor for your bank, UPI, the income tax portal, and anything linked to Aadhaar.
- Prepaid numbers lapse after a period of no use and can eventually be reassigned to somebody else. The exact period varies by operator and changes, so do not rely on a remembered figure.
- Many Indian banks now accept an overseas mobile number for OTPs, but coverage varies by bank and by country. It is worth asking before you need it.
- Changing an Aadhaar-linked number is the hardest of these to fix remotely, so deal with it on a trip rather than in an emergency.
What actually breaks
It helps to see how much is hanging off one number. When it stops working, this is the list that stops with it.
| What stops | Why | How hard to fix from abroad |
|---|---|---|
| Net banking and card transactions | OTP goes to the registered mobile | Moderate. Many banks accept an overseas number |
| UPI | The number is the identity on which UPI is registered | Moderate. Needs a number the bank and NPCI recognise |
| Income tax e-filing | OTP for login and for verifying a return | Easier. Email and other verification routes exist |
| Aadhaar based services and DigiLocker | Aadhaar OTP goes to the Aadhaar-linked number | Hard. Changing it generally needs an enrolment centre in India |
| Bank re-KYC by video | The session is authenticated against the registered number | Moderate, and it blocks the fix for a blocked account |
That last row is the one that catches people out. The number is often what you need in order to fix the account, which means losing it can lock you out of the very process designed to let you back in.
If you still have the number, keep it
This is far cheaper than recovering it later. The number does not have to be the one you use day to day. It has to be one that stays alive and that you can read messages on.
- Keep it on a plan that does not lapse. A postpaid connection held by you, billed to an account you still fund, is the most durable option.
- If it is prepaid, recharge it on a schedule rather than when you remember. Set a calendar reminder, because the consequence of forgetting is not a lapsed SIM, it is a recycled number.
- Keep the SIM in a basic handset in India that somebody can read for you, or in a dual SIM phone you carry.
- Check that the number is registered in your own name. A number in a parent's or sibling's name is a problem the day you need the operator to act on it.
- Do not let it sit unused for long stretches even while recharged. Operators treat prolonged inactivity differently from non-payment.
When a number is released and reassigned, a stranger receives the codes your bank sends. Treat the loss of a number as something to report to your bank immediately, not as an inconvenience to sort out on the next trip.
Registering an overseas number instead
A lot of NRIs do not know this is possible. Many Indian banks will register an international mobile number against the account and send OTPs to it. Support is uneven, so the questions to ask are specific: does the bank support an overseas number at all, does it support your country code, does it apply to net banking as well as card transactions, and does it work for UPI.
UPI is the one with the most moving parts. NPCI permits UPI on NRE and NRO accounts with international numbers from a defined list of countries, and the bank has to support it too. If UPI matters to you, confirm both ends rather than assuming the bank's general policy covers it.
Where an overseas number is not supported, ask about alternatives before you accept that nothing can be done. Email OTP, a hardware or software token, and call-back verification all exist at various banks, and the branch often does not volunteer them.
If the number is already gone
Changing the registered number at the bank is usually a form, your identity documents and, depending on the bank, attestation abroad. It is the same attestation question that governs re-KYC, so if both are outstanding, do them together in one package rather than two.
Aadhaar is the stubborn one. Updating the mobile number linked to Aadhaar generally requires attending an enrolment centre in person, and it cannot be done online. If you hold Aadhaar and expect to need Aadhaar OTP for anything, treat the next trip to India as the window and book the appointment before you fly.
Can I keep an Indian number purely for OTPs without using it?
Yes, and many NRIs do. A postpaid connection in your own name, lightly used and reliably paid, is the most durable form. The point is that it stays active and that you can read what arrives on it.
My Indian number is in my father's name. Is that a problem?
It works until it does not. The day the operator needs instructions, or the day the account holder is unwell or no longer living, you have no standing to act on the number. Move it into your own name while that is easy.
Will my bank send OTPs to a foreign number?
Many will, but it varies by bank and by country, and support for net banking, cards and UPI is not always the same. Ask about each one specifically rather than accepting a general yes.
Do I need an Indian number to file my Indian tax return?
Not necessarily. The e-filing portal supports verification routes that do not depend on an Indian mobile. It is Aadhaar OTP specifically that ties back to the Aadhaar-linked number.
What if the number was reassigned to someone else?
Tell your bank straight away and get the registered number changed. Do not try to reclaim the number from the new holder. Assume anything sent to it in the interim was seen by a stranger and check your account for unauthorised activity.
This article is for general information only and reflects rules current as of 2026. It is not legal, tax, or financial advice. Rules, rates and procedures change, and bank and operator practice varies, so please confirm the current position with a qualified professional before acting.